Prospective randomized study of mode switching in a clinical trial of pacemaker therapy for sinus node dysfunction.

Journal Article (Clinical Trial;Journal Article;Multicenter Study)

INTRODUCTION: Atrial fibrillation (AF) is common in pacemaker patients with sinus node dysfunction (SND) and may result in rapid ventricular pacing (RVP) in the DDDR mode. Mode switching (MS) reduces RVP, but its clinical benefit in patients with SND is unknown. METHODS AND RESULTS: Two hundred two patients in the Mode Selection Trial (MOST; 2,010-patient, 6-year trial of DDDR vs VVIR pacing in SND) randomized to DDDR pacemakers with atrial high-rate episode (AHRE) storage capabilities were subrandomized to MS ON (N = 96) or MS OFF (N = 106). Cardiovascular symptoms, quality of life (QOL), reprogramming due to RVP, death, stroke, and heart failure hospitalization (HFH) were compared between groups. The treatment groups were similar with regard to AF history (59% MS ON vs 57% MS OFF). AHREs occurred in 49% patients during median follow-up of 2.2 years. Median AHRE duration (in min; MS ON 116 vs MS OFF 58, P = 0.29), frequency AHREs/week (MS ON 3.5 vs MS OFF 6.4, P = 0.23), and time spent in AHRE (min/week) (MS ON 450, MS OFF 268) were similar. Reprogramming due to any RVP during AHREs occurred more in MS OFF vs MS ON (13.2% vs 3.1%, P = 0.011) and marginally more for symptomatic RVP (8.5% vs 2.1%, P = 0.062). Cardiovascular symptoms occurred in 93.6% MS ON vs 90.2% MS OFF (P = 0.38). Median number of symptoms reported per visit was similar (MS ON 1.3 vs MS OFF 1.5, P = 0.62). Median symptom frequency/severity, summed and averaged over visits, was similar (MS ON 4.3 vs MS OFF 4.5, P = 0.74). QOL was not different between groups. Death, stroke, and HFH were not different between groups. CONCLUSION: MS reduces pacemaker reprogramming due to RVP during AHREs in a small number of patients but does not improve QOL or cardiovascular symptoms overall among patients with SND.

Full Text

Duke Authors

Cited Authors

  • Sweeney, MO; Hellkamp, AS; Ellenbogen, KA; Glotzer, TV; Silverman, R; Yee, R; Lee, KL; Lamas, GA; MOST Investigators,

Published Date

  • February 2004

Published In

Volume / Issue

  • 15 / 2

Start / End Page

  • 153 - 160

PubMed ID

  • 15028043

International Standard Serial Number (ISSN)

  • 1045-3873

Digital Object Identifier (DOI)

  • 10.1046/j.1540-8167.2004.03146.x


  • eng

Conference Location

  • United States